The invention relates generally to welding torches, and more specifically, to systems that allow for operator adjustment of wire feed speeds in the torch handle.
A wide range of welding systems and welding control regimes have been implemented for various purposes. For example, metal inert gas (MIG) techniques allow for formation of a continuing weld bead by feeding welding wire shielded by inert gas from a welding torch. Electrical power is applied to the welding wire and a circuit is completed through the workpiece to sustain an arc that melts the wire and the workpiece to form the desired weld.
The welding torch may include features so that an operator may adjust various operating parameters of the welding system. For example, it may be desirable to adjust a wire feed speed at various times during the welding operation. In many applications, this requires that the welding operator interrupt his/her work and make an adjustment at the wire feeder, which may be at some distance from the workpiece. In other cases, an adjustment is provided on the torch handle, but this may be subject to inadvertent adjustment due to its placement. That is, the operator may mistakenly adjust the wire feed speed, or the welding torch may brush up against an obstacle, resulting in advertent adjustment of the wire feed speed. This inadvertent adjustment may result in a poor quality weld with associated rework, and additional time and effort for the operator to monitor and readjust the weld parameters to the desired value.
Such adjustability may be particularly useful in torches that draw wire by virtue of a motor included in the torch body. Such torches are commonly used in applications using aluminum and aluminum alloy wires that are both pushed by a motor in a wire feeder and pulled by a small motor in the torch. In such cases, the adjustment may affect the rate of rotation of the wire feeder motor, the torch motor, or both.